1. Field of the Invention
The present invention is a sampling method and a device for obtaining real time, accurate measurements of the fluid composition and mass flow rates in conduits having uniform or non-uniform fluid composition, velocity and temperature profiles. The present invention includes the sampling of all fluids, including gases, aerosols, particulates, liquids and combinations of the same.
2. Description of Related Art
The problem of obtaining real-time accurate measurements of aerosol and gas in processes in conduits with uniform or non-uniform gas velocity, composition, temperature profiles, swirl and turbulence is a common one. Simply inserting a single-point gas sampling probe into a conduit of unknown characteristics only samples the fluid composition in one location which is not representative of the entire flow field in the conduit. The largest error is generally due to the velocity which can easily vary by a factor of five, the composition by a factor of three and temperature by 50% in combustion applications such as in a large coal-fired boiler, for example. In this example, measurement of the excess oxygen and carbon monoxide is a vital parameter to control combustion and improve plant efficiency. Measurement of the emission of particulates from all processes is very important for pollution control. The present invention can also be used to measure particulates as well.
The applicant is aware of the following references which relate to sampling and measurement of fluid flowing in a conduit.
U.S. Pat. No.Inventor(s)2,523,721Russell et al2,614,423Carbone4,115,229Capone4,290,315Grönberg6,164,142Dimeff6,642,720Maylotte et al6,843,104Busch6,862,915Staphanos et al2003/018,586Orieskie et al
Russell et al disclose an apparatus for analyzing gaseous fuel before it is delivered into the heating chamber. A sample is collected and burned under controlled conditions. The combustion products are analyzed.
Carbone discloses the measurement of fluid flow through a conduit across the cross-sectional area of the conduit. The mean total differential between the impact pressure and the static pressure actuates a measuring and recording metering mechanism.
Capone discloses a gas analyzer for analysis of explosive mixtures. A correction loop flow circuit is used to bring a sample past a gas sensing element and back to a common inlet-outlet chamber.
Gröberg discloses an apparatus for determining the differential pressure and the volumetric fluid flow in a conduit. There is a pipe loop provided with a series of ports for sensing pressure.
Dimeff discloses an air flow measuring device which present a restricted orifice to the air flow and measure the pressure drop to determine the flow rate.
Maylotte et al disclose a wireless sensor assembly for measuring selected properties of a gas stream.
Busch discloses a system for measuring gaseous constituents in a flowing gas mixture. A mixing device in a flow homogenizes the gas mixture before it is detected by the sensor which detects individual gas constituents.
Staphanoes et al disclose a combustion gas analyzer for measuring the concentration of a gas constituent in an exhaust gas stream.
Orieskie et al disclose a process flow device which has a self-averaging orifice plate. The volumetric rate of flow is measured by a differential pressure process.
None of these references disclose a method of using one or more sampling nozzles which direct the fluid sample flow into a manifold wherein the flow rate and composition of the conduit fluid may be analyzed from a small sample stream of fluid having the same properties of the fluid in the conduit, nor a method in which the sample streams are collected independent of each other and collect a sample that represents the product of the fluid composition and the conduit mass flow rate at each nozzle or hole in the probe.